The present invention relates to swim fins with reduced drag coefficients. The swim fins have a shoe, a center guide attached to the shoe, and a wing pivotally attached to each side of the center guide by hinges.
Scuba divers and some swimmers use swim fins to convert leg movement into propulsion through the water. Each swim fin generally includes a shoe with a blade attached to the front. A big blade for propulsion in water requires big and strong leg muscles. The larger the blade, the faster the scuba diver or swimmer moves, and the quicker leg fatigue sets in. Swimmers move their legs in an up and down motion, referred to as a kick, to propel themselves in the water. Most fins work in both directions of the swimmer's kick. However, a swimmer has far less muscular power for the upstroke than for the down stroke of a kick. As a result, there is less power available in the up stroke than the down stroke of each kick and less propulsion is obtained from the up stroke. Unfortunately, the exertion or work on the part of the scuba diver or swimmer is not substantially reduced during the up stroke when using two stage swim fins that provide propulsion in both directions of a swimmer's kick. Swim fins have been proposed which provide single stage propulsion in that they provide maximum propulsion during the down stroke and minimum propulsion during the up stroke. Such single stage swim fins reduce leg fatigue. The single stage swim fins that have been used in the past have had poor durability and high drag. The high drag has resulted in decreased speed and quicker leg fatigue.